The prior art includes many examples of flexible hose coupling devices that employ a barbed nipple and a socket where the hose is clamped with a crush (compression) force between the nipple and the socket. The crush force is typically generated by crimping the socket down onto the outside of the hose where it is trapped between the socket and the barbed nipple. U.S. Pat. No. 4,804,212 to Vyse discloses a device to crimp the socket onto a hose and nipple. The nipple has a central passageway for the flow of hydraulic fluid there through. The nipple is then connected to some type of hydraulic device such as a valve or pump, etc. The hose is retained on the nipple by the crush force between the socket and the nipple which is generated as the socket is crimped so as to trap the hose between the nipple and the socket. At higher pressures, this connection between the couple device (fitting) and the hose may begin to leak and there may even be complete separation between the hose and the fitting at high pressures. U.S. Pat. No. 5,417,461 to Dougherty et al. discloses an alternate retention mechanism to the barbs on the nipple, where there are ridges formed on the outside of the nipple and the socket is rolled to compress the hose onto the ridges.
The crush or compression force on the hose between the socket and the nipple remains at a maximum as it is was generated upon assembly when the socket was crimped. This compression force level may decrease slightly with time and upon the introduction of high pressure hydraulic fluid. The pressurized hydraulic fluid is tending to blow the hose off of the fitting and the retention forces generated by the socket crush and the barbs on the nipple must prevent the hose from leaking or separating from the nipple. This prevents the hose and fitting assembly from being used in applications where the hydraulic fluid pressure might exceed the recommended level. In these applications, more expensive fluid conveyance systems must be used such as more sophisticated hose fittings or even hard tubing. It would be desirable to employ a hose retention system that would allow the flexible hose and socket/nipple fitting to be used at higher pressures without leakage or separation. However, none of the prior art references disclose using a device that uses the working hydraulic fluid pressure to maintain or increase the compressive force on the hose for improved retention and improved sealing at higher pressures.
Due to an increasing demand for traditional hose coupling assemblies to operate without leakage, particularly in high pressure fluid systems or in systems that carry a working fluid that is difficult to seal against leakage. Accordingly, there continues to be a need for improved hose coupling assemblies that can operate in high performance fluid systems without leakage or failure.